In certain commercial packagings, it is necessary for two components of the packaged material to remain physically separated until just prior to use. This requirement is a result of a variety of constraints placed upon the packaged material because of its particular nature. For example, the two components may be required for adequate utility of the packaged material, but once mixed the two components or one of the components may rapidly deteriorate and destroy that required utility. An example of this is where a medicine must be administered in a solution, but the solution is not stable under ambient conditions. On the other hand, the two components may require separate packaging because of a reaction which takes place when the two components are mixed and the mixture must be used either during or shortly after the reaction takes place. An example of this is where the components when mixed foam and the mixed components must be used in a foamed condition. Other examples of such constraints placed on the packaged materials are well known to the art.
To provide containers of the foregoing nature, the art has proposed a variety of container constructions where some positive movement of an element of the container will allow the two components to mix. One approach in the art is that of providing special cooperating configurations of a moveable element and the container per se, such that a "valving" action is provided between that element and the container. This arrangement, however, requires special containers and does not lend itself to broad commercial application. The special containers not only substantially increase the cost of the package but are not handleable on conventional packaging machines. Also, in this approach of the art, the moveable element is often left in the container which is most unsatisfactory for certain applications, particularly where the entire contents are to be emptied and used. The movable element in the container constitutes a foreign object and the presence thereof is often both asthetically and functionally objectionable. U.S. Pat. No. 2,869,745, U.S. Pat. No. 3,464,714, U.S. Pat. No. 3,809,225, and U.S. Pat. No. 3,842,836 are representative of this art.
In a similar approach, the art has proposed telescoping upper and lower vessels for forming the two compartments with a displaceable plug in at least one of the compartments. Here again, special container configurations are required, at least on one of the vessels, and the displaceable plug is normally left in the mixed components. U.S. Pat. No. 3,314,563 is representative of this art.
The art has proposed other arrangements which may utilize more conventional lower containers, but require very special upper containers through which an action displaces a sealing plug between the two compartments and the package. Here again, the plug remains in the mixed components and is unacceptable for the reasons noted above. U.S. Pat. Nos. 2,524,607, 2,653,611, 2,781,141, 3,326,400, 3,493,823 and 3,539,794 are representative of this approach.
Valving mechanisms which do not require special lower containers have also been proposed, but these valving mechanisms have not been totally satisfactory. For example, in one such approach, the total valving mechanism communicates with the mixing components, as illustrated in U.S. Pat. No. 2,764,157. The removal of the contents of the package is difficult at best and that arrangement is useful only in very special cases. U.S. Pat. No. 2,793,776 proposes an alternate arrangement where a threaded device operates through a rod to move a plug from an upper container disposed in a lower container to discharge the contents from the upper container. This arrangement is not only relatively expensive to manufacture, but has the disadvantage that slowly opening the plug from the upper container only gradually allows the contents of the upper container to flow therefrom. When the contents of the upper container are subject to agglomeration on contact with the contents of the lower container, this slow opening can cause initial contact between the contents of the lower container and the upper container in such a gradual manner that agglomeration will occur and prevent the contents of the upper container from fully emptying even after the plug of the upper container is fully removed. This gradual dispensing of the contents of the upper container also fails to dispense the contents of the upper container uniformly throughout the contents of the lower container and this can cause difficulties in subsequent mixing.
In a variation of the foregoing arrangement, U.S. Pat. No. 3,924,741 proposes a slideable gate arrangement where an inside sleeve covers apertures in an outside sleeve and, by moving the inside sleeve upwardly, the apertures allow the contents of the upper container to flow therethrough. Here again, this results in a gradual release of the contents of the upper container in the manner discussed above in connection with U.S. Pat. No. 2,793,776 and suffers from the same disadvantages.
Finally, another approach in the art has been to provide a pierceable diaphram separating the two compartments of a two component package. However, this arrangement requires most careful manufacture of the diaphram, since if the diaphram is accidentially ruptured during handling, the package will be rendered useless. On the other hand, if the diaphram provides sufficient insurance to avoid accidental rupture, it may be difficult to rupture the diaphram when mixing is desired. Diaphram packages, therefore, have not been widely accepted in the art.
Under the circumstances, it would be of significant advantage in the art to provide a two component container where mixing of the two components can be more uniformly carried out and where agglomeration and the like of one component when dispersed in the other component is avoided. It would be further advantageous to the art to provide such containers where the likelihood of caking, and preventing full discharge of the contents of the upper compartment is essentially avoided.